• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.4
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• pp.354-361
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• 1981

This study aims to compare stress concentratior factors in a loaded elastic body of the infinite plate with pressure coefficients of a fluid in the potential flow. First in view of hydrodynamics, when a single elliptic cylinder in the form of a bluff body stands in the potential flow, the pressure distribution(doefficient, C$\_$p/around the elliptic cylicder which is changed according to the position(angular displacements)is theoretically analyzed and calulated; secondly, in view of theory of elasticity, when an eliptic hole which is made on a flat plate gets tension, the stress distribution(factor) around the elliptic hole which is changed according to the position(angular displacements )is theoretically(K$\_$t/) and experimentally (K$\_$e/) measured; and finally. The results are compard and examined.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.465-470
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• 2002

For measuring friction-factor of artificially-roughened surfaces which are usually applied on damper seals, flat plate test apparatus is designed and fabricated. the measurement of leakage and pressure distribution through round-hole pattern specimen with different hole area is described and a method is discussed for determining the friction-factor experimentally. Results show that the friction-factor of the round-hole pattern surfaces is bigger than that of smooth surface and increases as increasing the hole area. A empirical friction factor model for round-hole pattern surface is defined as the Moody's friction factor formula.

• The KSFM Journal of Fluid Machinery
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• v.6 no.3 s.20
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• pp.15-20
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• 2003

For measuring friction factor of artificially-roughened surfaces which are usually applied to damper seals, flat plate test apparatus is designed and fabricated. The measurements of leakage flow and pressure distribution through round-hole patterned specimen with different hole areas are described, and a method is discussed for determining the friction factor experimentally. Results show that the friction factor of the round-hole patterned surface is bigger than that of smooth surface, and increases as increasing the hole area. A empirical friction factor model for the round-hole patterned surface can be descrived by the Moody's friction factor formula.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.209-216
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• 2016

Holes of rivets, bolts and nuts may cause stress concentration on the plates used in aircraft, ship and other structures. Excessive stress concentration may lead to severe breakage of the plates. Thus, accurate analysis of the stress concentration at the design stage will be important. In this paper, accuracy of EDISON program in stress concentration analysis was examined. By changing hole size on a narrow plate, the change of the stress concentration factor(K) was investigated. Additionally, the same experiment was conducted about series of holes on plate to investigate the interaction between adjacent holes. Then, these numerical results were compared with the analytic prediction. EDISON program showed very high accuracy about stress concentration, since the numerical results was correlated well with the analytic prediction.

• International Journal of Aerospace System Engineering
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• v.1 no.1
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• pp.1-9
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• 2014

In this paper, the effects of the anti-vortex hole angle and blowing ratio on the flat plate film cooling effectiveness were experimentally investigated. For the film cooling effectiveness measurement, pressure sensitive paint technique was applied. The experiments were conducted for cylindrical and anti-vortex film cooling holes, and three blowing ratios of 0.25, 0.5, and 1.0 were tested. Two anti-vortex hole angles of 0 and 15 degree with respect to the flow direction were considered. For the cylindrical hole case, the film cooling effectiveness decreased as the blowing ratio increased because of the coolant lift-off. For the angle anti-vortex hole cases, however, higher blowing ratio resulted in higher film cooling effectiveness due to the reduced actual blowing ratio and diminished kidney vortex. For all blowing ratio, the angled anti-vortex hole case showed the highest film cooling effectiveness.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.130-136
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• 2003

A FQI(fatigue quality index) analysis using the concept of SF(severity factor) is performed to various shape of elliptical hole. FQI is fatigue quality index to estimate the dynamic SF from static SF by finite element analysis. Since the SF is affected by the location of cutout in plate and radius ratio, static SF is analyzed with finite element method and forms the equation of FQI for predicting a dynamic SF. To examine the validity, dynamic SF is measured by photoelastics and thermalelastics for an epoxy resin plate with various elliptical holes under dynamic load.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.5-10
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• 2014

In this paper, the experimental study was carried to investigate the effect of angle of the anti-vortex holes on the film cooling effectiveness on a flat plate. The pressure sensitive paint technique was applied to measure the film cooling effectiveness. Two anti-vortex hole angles of $0^{\circ}$ and $15^{\circ}$ with respect to the primary hole were considered, and the simple cylindrical hole case was also tested. The blowing ratio based on the cylindrical hole was 0.5 and the same flow rate was kept for all anti-vortex hole cases. Results showed that the film cooling effectiveness for the anti-vortex hole cases were much higher than that of the cylindrical case. Among the anti-vortex hole cases, $15^{\circ}$ angle anti-vortex hole case showed higher film cooling effectiveness than that by the $0^{\circ}$ angle anti-vortex hole case.

• Interaction and multiscale mechanics
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• v.2 no.2
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• pp.177-187
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• 2009

Machine or structural members subjected to fatigue loading will have a crack initiated during early part of their life. Therefore analysis of members with cracks and other discontinuities is very important. Finite element method has enjoyed widespread use in engineering, but it is not convenient for crack problems as the region very close to crack tip is to be discretized with very fine mesh. However, as the body force method (BFM), requires only the boundary of the discontinuity (crack or hole) to be discretized it is easy versatile technique to analyze such problems. In the present work fundamental solution for concentrated load x + iy acting in the semi-infinite plate at an arbitrary point $z_0=x_0+iy_0$ is considered. These fundamental solutions are in complex form ${\phi}(z)$ and ${\psi}(z)$ (England 1971). These potentials are known as Melan potentials (Ramakrishna 1994). A crack in the semi-infinite plate as shown in Fig. 1 is considered. This crack is divided into number of divisions. By applying pair of body forces on a division, the resultant forces on the remaining 'N'divisions are to be found for which ${\phi}_1(z)$ and ${\psi}_1(z)$ are derived. Body force method is applied to calculate stress intensity factor for crack in semi-infinite plate. Also for the case of crack emanating from circular hole in semi-infinite plate radial stress, hoop stress and shear stress are calculated around the hole and crack. Convergent results are obtained by body force method. These results are compared with FEM results.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2219-2226
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• 2003

Two perforated plates are placed in parallel and staggered arrangements with a gap distance of 2 times of the hole diameter, and initial crossflow passes between the plates. Both the injection and effusion hole diameters are 10 mm, and the Reynolds number based on the hole diameter and hole-to-hole pitch are fixed to 10,000 and 6 times of the hole diameter, respectively. To investigate the effect of crossflow, the flow rate of crossflow is changed from 0.2 to 2 times of that of the impinging jet. A naphthalene sublimation method is used to determine the local heat/mass transfer coefficients on the upward facing surface of the effusion plate. With the initial crossflow, the heat/mass transfer rates on the effusion (target) plate decrease as the velocity of crossflow increases, since the crossflow induces the locally low transfer regions formed at the mid-way between the effusion holes. However, the impingement/effusion cooling with crossflow presents higher heat/mass transfer rates than the array jet impingement cooling with the same initial crossflow.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1398-1407
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• 2005

This paper is concerned with the vibration analysis of a rectangular plate with a rectangular hole. Even though there have been many methods developed for the addressed problem, they suffer from computational time. In this paper, we developed a new methodology called Independent Coordinate Coupling Method which can couple two independent coordinate systems for the entire plate domain and the hole. By matching the deflection condition imposed on the expressions, the relationship between the global axes and the local axes is derived. This formula is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the proposed method.